Students get ready for an American education by poring through textbooks at private "schools of one."

SEOUL, South Korea — While his eighth grade classmates were studying for exams at Pakhyun Middle School in Seoul this fall, Jung-Min Ku dropped out to prepare for a new life at an American boarding school.

These days, instead of reaching for his blue uniform in the morning, he pulls on jeans and a sweatshirt and goes to a private academy where he attends a school of one. He spends hours each day in a closet-sized classroom, working through American text books and practicing English grammar. With help from a personal tutor, he’s catching up on the first half of the eighth grade curriculum at San Marcos Academy in Texas, where he will enroll this January.

The 14-year-old boy took a break from studying on a December afternoon and practiced an introduction he might use at his new school: “Hi. My name is Jason and I like sports. Nice to meet you.”

South Korea has been a leading sender of students to the United States for two decades. More than 70,000 students were enrolled in American colleges and universities last year, a figure outpaced only by China and India. Increasingly, Korean students are leaving home earlier — going abroad for high school or even middle school — so they can learn English and have a better chance at admission to American colleges.

American schools offer more creative instruction and an alternate way up the career ladder. Students with average grades or study skills have a difficult time gaining entrance to Korea’s ultra-competitive universities, which are crucial gatekeepers for well paid and respected jobs. But American degrees and English fluency are also highly prized in the job market here.

How young is too young for a South Korean student to leave home to study abroad? Join the conversation in the comment section below.

How young is too young for a South Korean student to leave home to study abroad? Join the conversation in the comment section below.

Still, going abroad is expensive, with a price tag of up to $70,000 per year for tuition and related costs. And the transition can be jarring. Studies have shown that even the most academically successful Korean students struggle when they get to Ivy League colleges, and many drop out. For younger students, the shift can be more stressful.

Independence is a big change, said Ock-Kyung Chun, an educational adviser who is working with Ku. “For many Korean students, their schedule is not their schedule. Mothers and teachers design it and plan everything for them,” she said.

That’s one reason Chun and scores of other agencies offer intensive preparation courses to students before they set sail. Her study-abroad students typically spend from two to five months gearing up, depending on their English skills or academic needs.

In addition to getting academic lessons, the students prepare for new expectations, such as speaking up in class or getting involved in sports or after-school clubs. And they learn about different taboos, such as plagiarism. In Korea, copying information from the internet for a school assignment is normal, but in the United States, it can get you expelled.